Crossview 3D mode: HUD not beeing the nearest thing in the scene disrupts the 3D effect

Luanti version

Luanti 5.17.0 (Windows)
Using LuaJIT 2.1.1782726002
Built by Clang 22.1
Running on Windows/10.0.26100 x86_64
BUILD_TYPE=Release
RUN_IN_PLACE=0
USE_CURL=1
USE_GETTEXT=1
USE_SOUND=1
STATIC_SHAREDIR="."
STATIC_LOCALEDIR="locale"

Operating system and version

Windows 11 25H2

CPU model

12th Gen Intel(R) Core(TM) i7-12700H

GPU model

NVIDIA GeForce RTX 3070 Ti Laptop GPU

Active renderer

4.6.0 / opengl3 / SDL 2.32.10

Summary

If you play with 3D mode crossview enabled, the HUD is not the nearest thing in the scene. Because the HUD is drawn on top of the surroundings, what the user sees is contradictory: the 3D effect becomes weird and you cannot see the HUD clearly anymore (see screenshots). This happens to all the HUD elements but is most noticeable if there are larger HUD elements like text in the middle of the screen.

Changing the 3D mode parallax strength does not fix this issue; it just makes it worse. At the default value of 0.025 the HUD appears to be around 4 meters away, at the maximum value of 0.087 it is 8 meters away. While decreasing the value reduces the HUD distance, the 3D effect diminishes more and more.

To fix this, the HUD should appear, regardless of the parallax strength setting, always as the nearest thing, nearer than all the surroundings (having a distance of less than 0).

Screenshots

The leaves appear to be nearer than the text:

Looking directly at very near nodes disrupts the 3D effect and seeing the HUD clearly:

Steps to reproduce

1. Open Settings/Graphics and select crossview under 3d mode, then start a game
2. For example: stand directly in front of a block and look at the HUD